Dart and B.B. gun shooting are very popular indoor games because they need no sophisticated or expensive equipments and the rules are simple. Thus, the dart game is now a popular entertainment in both home and social activity. The dart game generally uses darts to shoot a dartboard on which a pattern indicating different scores is provided. The dartboard is usually hung on for example a wall and is usually kept on the wall even when the game is not played. Besides being simply hung on the wall, the dartboard provides no other function. It is therefore desirable to make use of the dartboard which is simply hung on the wall when not in use.